Atomizer with tilted orifice plate and replacement reservoir for same

ABSTRACT

A vibratory plate liquid atomization device ( 10 ) having a tilted orifice plate ( 34 ) which is vibrated by a piezoelectric actuator ( 36 ); and a novel replaceable liquid reservoir ( 40 ) having a vertically extending, dimensionally stable, liquid delivery system ( 44 ) with a non-horizontal upper surface ( 44   a ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to replaceable liquid reservoirs and moreparticularly to reservoirs which are provided with capillary type liquiddelivery systems for delivering liquid from within a reservoir to avibrating atomizer plate located above the reservoir.

2. Description of the Related Art

U.S. Pat. Nos. 4,301,093 and 5,657,926 show vibrating plate atomizers inwhich a reservoir is held beneath a piezoelectrically driven vibratoryatomization plate. A capillary type liquid delivery system, comprising afabric wick, extends up from within the reservoir to a location underthe vibrating atomization plate to deliver liquid from within thereservoir to the underside of the plate to be atomized thereby.

U.S. Pat. No. 5,518,179 also shows a vibratory type atomizer in whichliquid from a fluid source is delivered by a foam capillary materialwhich is lightly compressed against a vibratory perforate membrane. Theperforate membrane is shown to be located in a vertical plane; and thefoam capillary material is shown to extend upwardly from the fluidsource and to be bent through 90° so that its upper end rests flatagainst the face of the perforate membrane.

Other atomizing devices which atomize liquids from a reservoir by meansof a vibrating plate and which use a liquid delivery system to transferthe liquid from the reservoir to the plate are shown in U.S. Pat. Nos.4,294,407, 4,479,609, 4,790,479, 4,793,339, 5,297,734, 5,299,739 and5,996,903.

It is often necessary or desirable to orient the vibratory orifice plateof an atomizer device so that it ejects atomized or aerosolized liquiddroplets at an angle to the vertical. For example, where the atomizationdevice is to be mounted on a wall, the ejected liquid droplets should bedirected away from the wall so that they do not collect and do damage tothe wall surface. This problem can be overcome by orienting thevibratory perforate membrane or orifice plate so that its plane istilted from the horizontal and away from nearby walls or other verticalsurfaces.

A problem occurs when liquid is to be transferred by capillary actionfrom a reservoir to a vibrating perforate membrane or vibrating orificeplate which does not extend in a horizontal plane. In the past, theliquid delivery systems of vibratory type atomization devices, whichusually comprised a fabric wick or a solid capillary element, exitedfrom the reservoir in a vertical direction and then became bent at alocation above the reservoir so that the upper end of the capillaryelement terminated flat against the surface of the perforate membrane ororifice plate. As a result, there was a tendency for liquid to drip fromthe capillary element and accumulate outside the reservoir without beingatomized or recoverable. Also where the liquid is aggressive, forexample in the case of many liquid fragrances or insecticides, suchleakage of the liquid can damage the surfaces on which it accumulates.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a novelatomizer for ejecting small liquid droplets into the atmosphere. Thisnovel atomizer comprises a housing, a vibratory orifice plate whichextends in a plane and which is mounted in the housing with its planetilted from the horizontal. The orifice plate has a plurality of smallorifices formed in its center region. A vibratory actuator is coupled tothe orifice plate for causing it to vibrate rapidly in a directionperpendicular to its plane.

A replaceable liquid reservoir is removably mounted within the housingbelow the orifice plate. The reservoir comprises a liquid container forcontaining a supply of liquid to be atomized; and it further comprises asolid, porous and dimensionally stable elongated liquid delivery member.The liquid delivery member extends up along a vertical axis from alocation within and near the bottom of the liquid container and throughan upper opening in the container to a location above the container. Theliquid delivery member has an upper end which is located above thecontainer and which forms an upper liquid delivery surface. The liquiddelivery surface itself is tilted from the horizontal and it ispositioned in the housing such that it lies along the plane of theorifice plate. As a result, maximum area of contact and maximumeffectiveness of liquid transfer is achieved between the liquid deliverysurface and the orifice plate. The liquid delivery surface at the upperend of the liquid delivery member is also contained within and does notextend beyond the extent of the horizontal cross-section of the liquiddelivery member. Consequently any excess liquid which comes off the edgeof the liquid delivery surface, merely runs back along a vertical sidesurface of the liquid delivery member and back into the liquid containerwithout dripping onto nearby surfaces outside the container.

According to another aspect of the invention, there is provided a novelreplaceable liquid reservoir for use with a vibrating orifice plateatomizer device. This novel reservoir comprises a liquid container forcontaining a supply of liquid to be atomized and a solid, porous andelongated, dimensionally stable, liquid delivery member which extendsalong a vertical axis from within the liquid container and out throughan upper opening of the container to a location along the vertical axisabove the liquid container. The liquid delivery member is formed with anupper end which is located along the vertical axis and above thecontainer. The upper end of the liquid delivery member is formed as aliquid delivery surface which intersects and forms an acute angle withthe vertical axis. Thus the liquid delivery surface can lay flat againsta tilted orifice plate within an atomizer device to provide maximumeffectiveness of liquid transfer to the tilted orifice plate. Further,the liquid delivery surface is contained within and does not extendbeyond the edge of a horizontal cross-section of the liquid deliverymember. Consequently excess liquid which flows from the edge of theliquid delivery surface, merely runs back along a vertical side surfaceof the liquid delivery member and back into the liquid container withoutdripping onto nearby surfaces outside the container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational section view of an atomizer according tothe invention;

FIG. 2 is an enlarged fragmentary view of a portion of the atomizerdevice indicated by a phantom line 2 in FIG. 1;

FIGS. 3 and 4 are side and front elevational views, respectively, of anovel replacement reservoir according to the invention;

FIGS. 5-8 are fragmentary views showing alternate forms of a liquiddelivery portion of the replacement reservoir of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, an atomizer device 10 according to the presentinvention is plugged into an electrical outlet 12 in a wall 14. Theatomizer device comprises a hollow outer housing 16 which has a flatmounting surface 18 from which electrical prongs 20 extend. These prongscan be plugged into the outlet 12 thereby to support the atomizer device10 and, at the same time, to provide it with electrical power.

The electrical prongs 20 are connected inside the housing 16 toelectrical circuits formed on a printed circuit board 22. The circuitson the printed circuit board 22, which may be as described in copendingapplication Ser. No. 10/005,655, filed on Dec. 3, 2001, producealternating electrical voltages on a pair of wires 24. The frequency andamplitude of these alternating voltages is controlled by the circuits onthe printed circuit board 22. In cases where the atomizer device isbattery driven, the manner in which these alternating voltages aregenerated may also be as described in U.S. Pat. No. 6,296,196.

The region of the housing 16 behind the mounting surface 18 is formed asa flared chimney 26. A slanted wall 28 extends across the interior ofthe chimney 26 and the wall 28 is formed with an ejection opening 32. Asbest shown in FIG. 2, an atomization assembly comprising a vibratoryorifice plate 34 and an annularly shaped piezoelectric actuator 36 arearranged just under, and in alignment with, the ejection opening 32.

The wires 24 connect the opposite sides of the actuator 36 with circuitsmounted on the printed circuit board 22. In this manner alternatingvoltages produced by these circuits impose alternating electrical fieldsacross the piezoelectric actuator and cause the actuator to expand andcontract in radial directions. The orifice plate 34 extends across andis affixed to the actuator 36, either directly or through anintermediate element, in a manner such that the radial expansion andcontraction of the actuator is communicated to the orifice plate andcauses it to vibrate up and down in a direction perpendicular to itsplane. The orifice plate 34 is provided in its center region with aplurality of small orifices which extend through the plate. Uponvibration of the plate, liquid which is supplied to the underside of theplate is broken up into small droplets and ejected upwardly from theupper surface of the plate and out through the ejection opening 32 inthe form of a puff or cloud 35.

It will be noted that the orifice plate 34, as well as the actuator 36are tilted from the horizontal in a direction away from the wall 14.This tilt allows the atomized liquid to be ejected in a direction awayform the wall 14 so that it does not impinge on the wall and damage itby chemical attack, etc.

Liquid is supplied to the orifice plate 34 from a replaceable liquidreservoir assembly 40 which comprises a liquid container 42 and a solid,porous and dimensionally stable liquid delivery system in the form of asolid capillary element 44. The capillary element extends upwardly alonga vertical axis A from within the container 42 and passes through anopening 46 in the top thereof to a fixed location adjacent the undersideof the orifice plate 34. A liquid to be atomized, which is containedwithin the liquid container 42, is drawn up out of the container bycapillary action in the capillary element 44 and supplied to theunderside of the orifice plate 34. The capillary element 44 is a solid,porous and dimensionally stable rod-like member. That is, the element 44contains minute interconnected open cells which form capillary passagesto draw liquid up from the liquid container 42 toward the upper end ofthe element 44.

In order to ensure that liquid will be delivered adequately and evenlyto the underside of the orifice plate 34, the capillary element 44 isformed with an upper surface 44 a which is tapered at the same anglefrom the vertical axis A as the tilt of the orifice plate. Thus theupper surface 44 a lies against the plate and provides maximum contactwith the plate. This tilt may be, for example, about 80° with respect tothe axis A; however the exact amount of the tilt is not critical to thisinvention, so long as it changes the direction along which the puff orcloud 35 of atomized particles is ejected, from vertical to a directionother than vertical.

It should be noted that the entire upper surface 44 a of the capillaryelement 44 is contained within the cross-sectional area of the element.Thus the capillary element 44 need not be curved or bent to provide flatcontact of its upper end with the plate 34. Because of this there is nodanger that liquid which does not become ejected by the orifice plate 34will drip onto surrounding regions of the atomizer assembly. At most,the excess liquid will run down the sides of the capillary element 44and back into the container 42.

As can be seen in FIG. 1, the reservoir assembly 40, including both theliquid container 42 and the capillary element 44 is removable as a unitfrom the atomizer device 10 so that it may be replaced with anotherreservoir assembly, for example when the liquid needs to be replenishedor when it is desired to atomize a different liquid. As shown in FIG. 1a lower portion 16 a of the housing 16 is resiliently bendable to holdthe liquid container 42 against an opposite inner wall 48 in thehousing. The inner wall 48 is formed with a shoulder or otherindentation 50 which locates the liquid container 42 in a specificpredetermined position within the housing 16; and it is held in place bythe resiliently bendable lower portion 16 a. When it is desired toremove and replace the reservoir assembly 40, it is only necessary topull down on the liquid container 42 so as to cause the lower portion 16a of the housing 16 to bend outwardly and allow the reservoir assembly40 to be pulled down and out from the atomizer device. A new reservoirassembly can then simply be inserted in the housing 16 and pushed intoplace so as to be held in a precise location within the atomizer device.

FIG. 3 shows the reservoir assembly 40, which is a self contained unit,removed from the atomizer device. As can be seen, the liquid container42 is formed with an open upper neck 52 which is closed by a plug 54.The plug 54 is open at its center; and the capillary element 44 extendsin a vertical direction from the bottom of the interior of the liquidcontainer 42 and out through the center of the plug 54 to apredetermined location above the liquid container. Because the capillaryelement 44 has a dimensionally stable construction (as opposed to thatof a fibrous wick), its tapered upper surface 44 a is thereby maintainedat a precise location above the liquid container 42. This allows thesurface 44 a to be positioned so that it lays against the underside ofthe orifice plate in the atomizer device without pressing too hard onit, thereby providing maximum effectiveness in the transfer of liquidfrom the capillary element to the orifice plate.

The capillary element 44 may be formed by bringing together smallparticles of a thermoplastic polymer and subjecting them to atemperature and pressure at which the molecules at the surface of eachsmall particle become mobile enough to mechanically intermingle with themolecules at the surface of any adjoining pellets, thus forming a bondbetween them. The small particles are maintained at a proper temperatureand temperature until a desired degree of bonding has occurred After anappropriate amount of time, the mass of small particles is cooled toroom temperature. The result is a porous structure molded into aspecific product shape. A suitable process for forming the capillaryelement 44 is described in U.S. Pat. No. 6,030,558.

FIG. 5 shows an alternative configuration for the capillary element 44.In the case of the configuration of FIG. 5, the element 44 is nottapered at the top but instead is cut at a slant relative to itslongitudinal axis. This forms an oval shaped upper surface 44 b asviewed in FIG. 5. The surface 44 b is inherently larger than the surface44 a in the embodiment of FIG. 3; and this makes the capillary elementmore suitable to larger diameter orifice plates. Conversely, it permitsa smaller diameter capillary element for a given diameter orifice plate.It will be noted that the surface 44 b is not symmetrical about thelongitudinal axis of the capillary element 44 as is the surface 44 a ofthe embodiment of FIG. 3. Because of this, the capillary element must beproperly oriented about its longitudinal axis A in order to be sure thatthe surface 44 b will lie flat against the surface of the orifice plate.

FIG. 6 shows a further alternate capillary element 45. In thisembodiment, the capillary element 45 has a rectangular rather than around cross-section. Otherwise it is of the same construction as thecapillary element 44. The rectangular configuration of the element 45,which is shown in FIG. 6 as square, permits many different possibilitiesfor its upper surface 45 a which abuts the orifice plate of a vibrationtype atomizer device. Firstly, as shown in FIG. 7, the capillary element45 may simply be cut from opposed sides to form two opposed slantedsurfaces 45 b and 45 c. If desired, these surfaces may extend atdifferent angles with respect to the axis A, which will permit thereservoir assembly 40 to be used with different atomizer devices whoseorifice plates are tilted at different angles. In another embodiment,shown in FIG. 8 the capillary element 45 may be formed with four flatsurfaces 45 d which extend up from each side to form a pyramidconfiguration.

The different arrangements described herein, provide different surfaceareas for the upper surface of the capillary element. A surface areashould be chosen such that it corresponds to the surface area of theorifice plate with which the capillary element is to be used. Also, ineach of the embodiments, the capillary element 44 or 45 should beoriented about its longitudinal axis A with respect to the liquidcontainer 42 such that when the liquid container is mounted in avibratory orifice plate type atomizer device, the flat upper surface ofthe capillary element will be oriented in the same direction as theorifice plate so that it will lie against the orifice plate.

INDUSTRIAL APPLICABILITY

This invention permits a vibrating plate type atomizer to operateeffectively to direct a cloud or mist of atomized droplets in adirection other than vertically above the atomizer. Thus, the cloud ormist can be projected from one side of a room in toward the center ofthe room. The invention additionally provides a novel replacementreservoir having a specially shaped wick which extends vertically upfrom a liquid container and which is capable of delivering liquidefficiently and effectively to a non-horizontal vibratory atomizationplate.

What is claimed is:
 1. An atomizer for ejecting small liquid dropletsinto the atmosphere, said atomizer comprising: a housing; a vibratoryorifice plate extending in a plane and mounted in said housing with saidplane tilted from the horizontal, said orifice plate having a pluralityof small orifices formed in a center region thereof; a vibratoryactuator coupled to said plate for causing said orifice plate to vibraterapidly in a direction perpendicular to its plane; and a replaceableliquid reservoir removably mounted in said housing below said orificeplate, said reservoir comprising a liquid container for containing asupply of liquid to be atomized and a solid, porous and dimensionallystable elongated liquid delivery member extending along a vertical axisfrom within said liquid container and out through an upper opening ofsaid container, said liquid delivery member having an upper end which isalso tilted from the horizontal and which is positioned in said housingsuch that it extends along a surface of said orifice plate.
 2. Anatomizer according to claim 1, wherein said liquid delivery member isformed with capillary pores which extend from one end to the oppositeend of said member.
 3. An atomizer according to claim 1, wherein saidupper end of said liquid delivery member has a flat surface.
 4. Anatomizer according to claim 1, wherein said upper end of said liquiddelivery member extends continuously at a fixed angle with respect tosaid vertical axis.
 5. An atomizer according to claim 1, wherein saidliquid delivery member has a circular cross-section.
 6. An atomizeraccording to claim 1, wherein said liquid delivery member has arectangular cross-section.
 7. An atomizer according to claim 1, whereinsaid upper end of said liquid delivery member comprises a pair of flatsurfaces which converge at said vertical axis.
 8. An atomizer accordingto claim 6, wherein said upper end of said liquid delivery membercomprises flat surfaces in a pyramidal arrangement.
 9. A replaceableliquid reservoir for use with a vibrating orifice plate atomizer device,said reservoir comprising: a liquid container for containing a supply ofliquid to be atomized; and an solid, porous and dimensionally stableelongated liquid delivery member extending along a vertical axis fromwithin said liquid container and out through an upper opening of saidcontainer, said liquid delivery member having an upper end located at apredetermined position above said container; and said upper end beingformed as a surface which intersects said vertical axis and forms anacute angle with said vertical axis.
 10. A liquid reservoir according toclaim 9, wherein said liquid delivery member is formed with capillarypores which extend from one end to the opposite end of said member. 11.A liquid reservoir according to claim 9, wherein said upper end of saidliquid delivery member has a flat surface.
 12. A liquid reservoiraccording to claim 9, wherein said upper end of said liquid deliverymember extends continuously at a fixed angle with respect to saidvertical axis.
 13. A liquid reservoir according to claim 9, wherein saidliquid delivery member has a circular cross-section.
 14. A liquidreservoir according to claim 9, wherein said liquid delivery member hasa rectangular cross-section.
 15. A liquid reservoir according to claim9, wherein said upper end of said liquid delivery member comprises apair of flat surfaces which converge at said vertical axis.
 16. A liquidreservoir according to claim 14, wherein said upper end of said liquiddelivery member comprises flat surfaces in a pyramidal arrangement.